Device for suppressing bobbin vibrations in winding machines

ABSTRACT

On a thread winding machine, a device for eliminating flutter or severe vibrations between a winding bobbin and a driving roll frictionally engaged with the bobbin, in which the bobbin and driving roll are mounted to move toward and away from each other as thread builds up on or moves off the bobbin. A pair of plates having flat surfaces in frictionally sliding contact with each other, one plate mounted rigidly on the frame of the machine and one on the moving part (bobbin or drive roll as the case may be) provides resistance to fluttering as the bobbin rotates against the drive roll. The contacting surfaces of the plates lie in a plane substantially perpendicular to the axis of the bobbin and drive roll. Means is provided to urge the plates together to increase the friction. In a preferred form one of the plates is the pole surfaces of a permanent magent and the cooperating plate is of magnetic metal.

United States Patent 1 1 Gritschke et a1.

[ DEVICE FOR SUPPRESSING BOBBIN VIBRATIONS IN WINDING MACHINES [75] Inventors: Martin Gritschke, Okarben; Bernd Kretschmann, Offenbach, both of Germany [73] Assignee: Zimmer Aktiengesellschaft,

Frankfurt, Germany 22 Filed: Nov. 15,1973

21 App1.No.:4l6,234

[30] Foreign Application Priority Data Nov. 16, 1972 Germany 2256270 [52] US. Cl. 242/18 B; 242/18 DD [51] llnt. Cl. B65h 54/52 [58] Field of Search 242/18 B, 18 DD, 18 R,

[56] References Cited UNITED STATES PATENTS 2,605,974 8/1952 Keith 242/18 DD 1 May 13, 1975 FOREIGN PATENTS OR APPLICATIONS 530,856 12/1940 United Kingdom.,.. 242/18 DD 736,162 9/1955 United Kingdom..... 242/18 DD 888,848 2/1962 United Kingdom 242/18 DD [57] ABSTRACT On a thread winding machine, a device for eliminating flutter or severe vibrations between a winding bobbin and a driving roll frictionally engaged with the bobbin, in which the bobbin and driving roll are mounted to move toward and away from each other as thread builds up on or moves off the bobbin. A pair of plates having flat surfaces in frictionally sliding contact with each other, one plate mounted rigidly on the frame of the machine and one on the moving part (bobbin or drive roll as the case may be) provides resistance to fluttering as the bobbin rotates against the drive roll. The contacting surfaces of the plates lie in a plane substantially perpendicular to the axis of the bobbin and drive roll. Means is provided to urge the plates together to increase the friction. ln a preferred form one of the plates is the pole surfaces of a permanent magent and the cooperating plate is of magnetic metal.

4 Claims, 8 Drawing Figures mama w 1 36975 3,883 .082

SHEET 10F 2 FIG. 1

FIG. 3

FIG. 4 22 am? FIG. 5 23 Pmmwm 3. 883 082 SHEET 2 UP 2 FIG. 6

DEVICE FOR SUPPRESSING BOBBIN VIBRATIONS IN WINDING MACHINES BACKGROUND OF THE INVENTION In winding machines such as are used, for example, for the winding of synthetic threads or yarns, friction drive has attained in actual practice a greater importance than axial or direct drive. The friction drive takes place through frictional contact between the cylindrical circumferences ofa drive roller and the bobbin, i.e., the cylindrical outer periphery of the bobbin winding itself. The parts are arranged in such a way that the bobbin is rotatable in fixed position on the machine, while the drive roller together with its drive motor is movably mounted and is pressed with as light as possible a contact pressure on the bobbin. There are also conventional machine arrangements in which the drive roller is mounted in fixed position and the pressable bobbin is movable. In these machines the movable part, be it the bobbin or the drive roller, is carried on the machine for movement in a path inclined toward the fixed part by means of a carriage or the like, or is fastened to the outer end of a swinging arm mounted on the ma' chine. The contact pressure between bobbin and drive roller is generated, depending on the construction type of the machine, by pull force, spring force, counterweights or gravity.

In these friction-drive winding machines, especially in the first few minutes after the starting of the thread to be wound on the bobbin tube, there frequently occurs a jumping or hopping of the movable part. The cause of this is an imbalance in or at the bobbin tube. This is due to an imperfectly round or unbalanced bobbin tube (as a rule reused a number of times) and- /or to an uneven distribution of the first thread layers on the circumference of the bobbin tube. The rotating imbalance produces undesirable vibrations of the winding machine, which impair the quality of the thread, adversely affect the winding build-up and can lead to troubles in the further processing of the bobbins. Moreover, the vibrations tend to ruin the bearings of the bobbin and of the drive roller.

THE PRIOR ART Hitherto this undesirable manifestation, which is also known as fluttering or dancing" of the bobbin on the friction drive roller (cf. Klare, Fritzsche, Grobe, Synthetische Fasern aus Polyamiden [Synthetic Threads from Polyamides], 1963, p. 281, lines 25 ff.) has been counteracted solely by imposing a sufficiently high contact pressure on the contacting rolls.

To insure elimination of fluttering, a much greater contact pressure between bobbin and drive roller is chosen than would be desirable for a friction drive without injury to the bobbin winding and the thread. This undesirable increased contact pressure force is still maintained after a winding build-up of about 5 to mm thick on the bobbin tube, whereupon a natural damping of the vibrations is brought about by the bobbin winding itself.

For suppressing vibrations of an empty bobbin tube resulting from imbalance it has been proposed previously to strengthen the contact pressure with the aid of a permanent magnet. In such constructions the permanent magnet, which is mounted either on the movable part or the fixed part, is disposed opposite a fixed or movable magnetizable plate with an interposed air gap. This air gap, however, rapidly increases in size as the bobbin builds up in diameter so that the force of the magnetic field declines markedly immediately after a very small increase in winding thickness Consequently, the ability of the magnetic force to suppress vibrations is nullified before the self-damping thickness of the winding on the bobbin tube has been reached.

THE INVENTION The structure of the invention is designed to avoid these disadvantages and provides a device which, in a simple way, effectively suppresses the imbalance vibrations during the critical phase of the winding buildup without substantially increasing the desired frictional contact pressure.

According to one embodiment of the invention, this problem is solved by providing a magnet attached to the movable part with its pole surface approximately perpendicular to the axis of the bobbin and the drive roller so that as the bobbin winding builds up, the magnet slides on a correspondingly aligned magnetizable counterplate or the like mounted in fixed position on the machine. According to the basic concept of the invention the suppression of vibrations is achieved by a frictional or shearing resistance, effective both as the bobbin and drive roller approach each other and as they move away from one another. Hitherto, vibrationdamping devices have been effective to increase contact pressure only in one direction, when the bobbin approaches the drive roller. A permanent magnet of low field strength, suitable for use in the device of the invention, is commercially available, for example such as that used for door closures. The frictional or sliding resistance of such a magnet of about 2 cm pole area amounts in direction of movement of the movable bobbin or of the movable drive roller only to about 250 p. With the device of the invention, even using severely-deformed bobbin tubes, any jumping or hopping is completely eliminated.

So that the pole surfaces of the magnet may adapt superficially to the rigidly secured counterplate, the magnet is mounted to swing expediently in an angular range of up to about 45 out of the plane of contact in either direction. Furthermore, it is advantageous to provide bevels on the edges of the counterplate surface facing the magnet to facilitate movement of the magnet over the edges and on to the running track of the counterplate. This insures that after the magnet has run off of the counterplate after build-up of a bobbin winding sufficient for self-damping and removal of the bobbin, it can move smoothly on to the contact surface of the counterplate.

The parts are arranged in such a way that when the bobbin tube is empty, the entire area of the flat pole surfaces of the magnet bear against the face of the counterplate. In this manner at the commencement of the winding process, i.e., in the case of maximum danger of the occurrence of imbalance vibrations, the full frictional resistance is employed.

To achieve a coefficient of friction that is sufficient and remains constant over the engagement length of pole surface and counterplate, the counterplate preferably is ground flat in the region of the running path of the magnet.

It is not necessary that the magnet run off of the counterplate after the thread builds up to a certain thickness on the bobbin. In another form of the invention, the counterplate, at least in the region of the running path of the magnet, has an extension made from an unmagnetizable material. The pole surface of the magnet remains aligned with respect to the counterplate, but as the magnet runs on to the extension plate, the frictional resistance due to magnetic action is interrupted because the extension plate is non-magnetic material.

In another form of the invention a friction plate or the like aligned approximately perpendicularly to the axes of the bobbin and of the drive roller is mounted on the movable part in place of the magnet. Spring force is employed to urge the plates together as they slide on one another as the bobbin winding builds up. This construction is also a simple means for efficient suppression of the undesired imbalance vibrations.

In a preferred construction of this form of the invention, the spring force is adjustable, so that the resistance provided by the sliding friction plates can be adjusted to accomodate the particular operating conditions of the winding machine. It is advantageous if the spring force is active only in the first phase of the bobbin winding build-up.

DETAILED DESCRIPTION Further details of the invention are explained in detail in the following description with the aid of drawings in which FIG. 1 is a schematic, partially broken away front view of a conventional winding machine equipped according to the invention with a magnet and cooperating counterplate; 1

FIG. 2 is a broken-off section along the line IIII of FIG. 1;

FIG. 3 shows, on a larger scale, a plan view of the counterplate which interacts with the magnet;

FIG. 4 is a section along the line lV-IV in FIG. 3, but with addition of a plan view of the magnet;

FIG. 5 is a section similar to FIG. 4 showing another embodiment of the counterplate;

FIG. 6 is a side elevational view of another conventional winding machine, equipped with another form of the damping device of the invention;

FIG. 7 shows, on a larger scale, a section along the line VII-VII of FIG. 6; and,

FIG. 8 is a partial section along the line VIII-VIII of FIG. 6.

The winding machine 1 shown in FIG. 1 receives thread 2 coming, for example, from a melt-spinning device, and has two preparation rollers 3, two godets 4, a traverse device 5, a drive roller 6 and a bobbin holder 7 provided with a chuck and rotatably mounted in the usual manner. A bobbin tube or core 8 made of hard cardboard is mounted on and locked to the holder 7. FIG. 1 shows the position of the drive roller in relation to the bobbin tube 8 at the beginning of the winding process, when there is no thread yet wound on the bobbin tube 8. The drive roller 6 together with its drive motor 9 (FIG. 2) and the traverse device 5 are mounted on a carriage 10 which slides on the inclined guide rod 11. By modification of the inclination of the guide rod 11 the contact pressure between drive roller 6 and bobbin winding can be varied. In addition to gravity contact pressure, pneumatic or hydraulic contact pressure devices may be provided. The winding machine described so far is conventional.

A magnet 12 which interacts with the counter plate 13 as shown in FIG. 1 is mounted on carriage 10. As is evident especially from FIG. 2, the counterplate 13 is releasable by means of the screw 14 and is fastened over an elongated'hole 15 (FIG. 3) adjustably to the frame 16 of the machine 1.

Details of the carriage 10 and of its guide roll 11 are not shown in more detail, because the invention does not extend to these parts.

As shown in FIGS. 3 and 4 there are two run-on bevels 17 arranged at the edges of counterplate 13. Between them is the running path 18, represented in broken lines, over which the pole surface of the magnet 12 slides. The steel counterplate 13 is ground flat at least in the area facing the pole area of the magnet 12 be tween the run-on bevels 17. As shown in FIG. 4, the magnet 12 includes a magnet casing 19 and the permanent-magnetic body 21 swingably mounted on a pivot 20. The magnet 12 is detachably fastened to the carriage 10 with the aid of bores 22 arranged in its casing 19.

As shown in FIG. 1 the pole surface of the magnet 12, when the bobbin tube 8 is empty, stands in full surface contact with the counterplate 13, so that in this position the greatest frictional resistance between magnet 12 and counterplate 13 is provided. As the build-up of thread increases the diameter of the winding on the bobbin tube 8, the carriage 10 is moved to the left, causing the magnet 12 fastened to it to slide over the counterplate 13, and ultimately completely off the counterplate.

The surface of the counterplate 23 shown in FIG. 5 is provided with the extension insert 24 made of an unmagnetizable material, for example, of a suitable plastic. This extension insert 24 is set into the surface to the counterplate 23, so that the insert and the counterplate 23 form a continuous flat surface facing the magnet. The extension insert 24 can be fastened to the counterplate 23 in a suitable manner, for example by cementing or riveting.

The winding machine 1' shown in FIG. 6 is constructed differently from the winding machine represented in FIG. 1. In the winding machine 1', the axes of the drive roller 6' and of the bobbin holder 7' do not run perpendicular to the front of the machine, but parallel to it. Furthermore, in this type of winding machine the drive roller 6 is fixed and the bobbin holder 7 is mounted on an axle on the outer end ofa swinging arms 25 which swings about pivot bearing 26 on the machine 1'. The thread course corresponds substantially to that described with reference to FIG. 1. This type of winding machine, too, is equipped with two godets 4' as well as with a traverse device 5. Bobbin tube 8' is slipped over the bobbin holder 7. Since also in this case the bobbin tube 8 does not yet carry any bobbin winding, FIG. 6 shows the machine at the beginning of the wind ing process. The parts of machine 1' so far described are conventional.

The device for suppressing imbalance vibrations is mounted on the swinging arm 25. It consists of a friction plate 27 movable with the swinging arm, and a counter-friction plate 28 interacting with it mounted in fixed position on the machine 1. For fastening the friction plate 27, a sleeve 29 is provided on the winding arm 25 in which there is slidably guided a cylindrical pin 30. The friction plate 27 is fastened to one end of the cylindrical pin, a stop 31 is formed on its other end.

The pin 30 is prevented by key 32 from turning in the sleeve 29. The annular surface of the friction plate 27 surrounding pin 30 has bearing upon it a coil pressure spring 33, which abuts at its other end against a pressure plate 34. There is play between pin 30 and the surrounding margin of the opening through the pressure plate 34. On the opposite side of the pressure plate are set screws 35 screwed into the swinging arm 25 to position the plate. The position of the screws relative to the swinging arm can be fixed by counter-nuts 36. It is evident that the spring 33 can be compressed more strongly by uniformly tightening the set screws 35, whereas loosening the set screws 35 leads to a reduction of the compressive force of the spring. In this manner the frictional resistance between the friction plate 27 and the counter-friction plate 28 is adjustable. The counter-friction plate 28 is fastened in a suitable manner, for example by rivets or screws (not shown) to a bracket 37 on the machine 1. The duration of the frictional engagement between the plates 27 and 28 during the bobbin winding build-up is governed by the length of the counter-friction plate 28, which extends in the direction of the pivotal movement of the swinging arm 25. In FIGS. 6 and 8 the counter-friction plate 28 has a run-on ramp 38, which facilitates sliding the plate 27 back on to plate 28 after the winding build-up is complete and the swinging arm 25 has moved past the end of plate 28. Friction plate 27 and/or counter-friction plate 28 can be treated on their contacting surfaces to modify the coefficient of friction. They can, of course, also be made from different materials.

The winding machine 1' represented in FIG. 6 can be equipped with a magnet and counterplate as shown in FIG. 1 in place of the two spring-loaded friction plates 27, 28. Conversely, the winding machine 1 represented in FIG. 1 can be equipped with the two spring-biased friction plates. A variation from the arrangement represented in FIG. 1, provides magnet 12 in fixed position while the counterplate 13 is fastened to the movable part, i.e, to the carriage 10. A corresponding modification can also be made in the winding machine 1 represented in FIG. 6 if the magnet and counterplate device is used in this machine.

What is claimed is:

1. An improved device for suppressing imbalance vibrations in the bobbin or drive roller of a friction-drive thread winding machine comprising:

first support means mounted on the thread winding machine for supporting the bobbin;

second support means mounted on the thread winding machine for supporting the drive roller, one of the first and second support means being relatively movable with respect to the other support means so as to permit the cylindrical surfaces of the bobbin and the drive rollers to move relatively into and out of contact with each other to rotate the bobbin as thread is being wound thereon;

friction means mounted on the movable one of the first and second support means for movement therewith, along a predetermined path of movement, the friction means having a first flat surface lying in a plane substantially perpendicular to the axes of the bobbin and the drive roller; and stationary plate means mounted rigidly on the thread winding machine adjacent to the path of movement of the friction means and having a second flat surface substantially parallel and opposed to the first flat surface of the friction means so that the flat surfaces may slide over each other as the bobbin and drive roller move away from and toward each other, the first and second flat surfaces being in surface-to-surface contact when the bobbin is empty and having their contact surface decrease as the winding diameter of the bobbin increases; with one of the first and second flat surfaces being the pole faces of a permanent magnet and the other of the flat surfaces being made of magnetic material.

2. The improved device described in claim 1 wherein the path of movement of the friction means is in a plane which is substantially parallel to the plane of the first and second flat surfaces.

3. The improved device described in claim 1 wherein the other surface of the first and second flat surfaces has a nonmagnetic insert in its face at the edge thereof remote from the area of contact between the flat surfaces when the bobbin is empty so as to reduce the magnetic force acting between the stationary plate means and the friction means as the bobbin and the drive roller move away from each other.

4. The improved device described in claim 1 wherein the stationary plate means has beveled edges at the terminal edges of the second flat surface to facilitate the first flat surface sliding up onto the second flat surface. 1: 

1. An improved device for suppressing imbalance vibrations in the bobbin or drive roller of a friction-drive thread winding machine comprising: first support means mounted on the thread winding machine for supporting the bobbin; second support means mounted on the thread winding machine for supporting the drive roller, one of the first and second support means being relatively movable with respect to the other support means so as to permit the cylindrical surfaces of the bobbin and the drive rollers to move relatively into and out of contact with each other to rotate the bobbin as thread is being wound thereon; friction means mounted on the movable one of the first and second support means for movement therewith, along a predetermined path of movement, the friction means having a first flat surface lying in a plane substantially perpendicular to the axes of the bobbin and the drive roller; and stationary plate means mounted rigidly on the thread winding machine adjacent to the path of movement of the friction means and having a second flat surface substantially parallel and opposed to the first flat surface of the friction means so that the flat surfaces may slide over each other as the bobbin and drive roller move away from and toward each other, the first and second flat surfaces being in surface-to-surface contact when the bobbin is empty and having their contact surface decrease as the winding diameter of the bobbin increases; with one of the first and second flat surfaces being the pole faces of a permanent magnet and the other of the flat surfaces being made of magnetic material.
 2. The improved device described in claim 1 wherein the path of movement of the friction means is in a plane which is substantially parallel to the plane of the first and second flat surfaces.
 3. The improved device described in claim 1 wherein the other surface of the first and second flat surfaces has a nonmagnetic insert in its face at the edge thereof remote from the area of contact between the flat surfaces when the bobbin is empty so as to reduce the magnetic force acting between the stationary plate means and the friction means as the bobbin and the drive roller move away from each other.
 4. The improved device described in claim 1 wherein the stationary plate means has beveled edges at the terminal edges of the second flat surface to facilitate the first flat surface sliding up onto the second flat surfacE. 